Should we provide a keyword than means (1/0) ?

[Ethan M. <merritt@u.washington.edu>]

I have noticed that many questions posted to the newsgroup
fall into the general category 
"How do I *not* plot part of my data or function?".
The answer usually involves a conditional expression with the
constant value  "1/0"   used to generate invalid data points.

I can see how it would be hard for new users to work this out
on their own.  "Illegal divide by zero" is not usually the 
same as "Omit this point" in the larger world.

So I wonder if it would be a good idea to add some keyword like
"skip" or "omit" or "invalid" or "undefined".  Instead of
writing
	plot <foo> using 1 : ($2 > 0 ? $2 : 1/0)
you could write
	plot <foo> using 1 : ($2 > 0 ? $2 : omit)


-- 
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center
Mailstop 357742
University of Washington, Seattle, WA 98195